Pad structure of wiring board and wiring board

Abstract

A pad structure for a circuit board including a phosphorus-containing nickel layer is provided, capable of improving a tensile strength of a solder member such as a solder ball mounted thereon or a foreign member soldered thereto. The pad structure ( 40 ) is a multi-layer plated structure provided in a conductor pattern of the substrate, for mounting the solder bump ( 20 ) thereon, and formed as part of the conductor pattern, including a metal layer ( 10 ) formed as part of the conductor pattern to constitute a pad body, a phosphorus-containing nickel layer ( 12 ) formed by an electroless nickel plating to be directly brought into contact with the metal layer, a copper layer ( 14 ) thinner than the nickel layer, formed on the nickel layer by an electroless copper plating, and a precious metal layer ( 16 ) formed on the copper layer by an electroless precious metal plating.

1 . A pad structure for a circuit board provided in a conductor pattern, to which a solder member such as a solder ball is mounted or a foreign member is soldered, having a multi-layer plated structure comprising 
 a metal layer formed as part of said conductor pattern to be a pad body,    a phosphorus-containing nickel layer formed by an electroless nickel plating to be directly brought into contact with said metal layer,    a copper layer thinner than said nickel layer, formed on said nickel layer by an electroless copper plating, and    a precious metal layer formed on said copper layer by an electroless precious metal plating.    
   
   
       2 . A pad structure for a circuit board as defined by  claim 1 , wherein said metal layer forming the pad body is formed of copper, and said precious metal layer is formed of gold, palladium or platinum.  
   
   
       3 . A pad structure for a circuit board provided in a conductor pattern, to which a solder member such as a solder ball is mounted or a foreign member is soldered, having a multi-layer plated structure comprising 
 a metal layer formed as part of said conductor pattern to be a pad body,    a phosphorus-containing nickel layer formed by an electroless nickel plating to be directly brought into contact with said metal layer,    a first precious metal layer formed on said nickel layer by an electroless precious metal plating,    a copper layer thinner than said nickel layer, formed on said first precious metal layer by an electroless copper plating, and    a second precious metal layer formed on said copper layer by an electroless precious metal plating.    
   
   
       4 . A pad structure for a circuit board as defined by  claim 3 , wherein said metal layer forming the pad body is formed of copper, and said first or second precious metal layer is formed of gold, palladium or platinum.  
   
   
       5 . A circuit board comprising 
 a substrate body,    a conductor pattern formed on said substrate body, having a pad in part thereof on which a solder member such as a solder ball is to be mounted or a foreign member is to be soldered, wherein    said pad comprises    a metal layer formed as part of said conductor pattern to be a pad body,    a phosphorus-containing nickel layer formed by an electroless nickel plating to be directly brought into contact with said metal layer,    a copper layer thinner than said nickel layer, formed on said nickel layer by an electroless copper plating, and    a precious metal layer formed on said copper layer by an electroless precious metal plating.    
   
   
       6 . A circuit board as defined by  claim 5 , wherein said metal layer forming the pad body is formed of copper, and said precious metal layer is formed of gold, palladium or platinum.  
   
   
       7 . A circuit board comprising 
 a substrate body,    a conductor pattern formed on said substrate body, having a pad in part thereof on which a solder member such as a solder ball is to be mounted or a foreign member is to be soldered, wherein    said pad comprises    a metal layer formed as part of said conductor pattern to be a pad body,    a phosphorus-containing nickel layer formed by an electroless nickel plating to be directly brought into contact with said metal layer,    a first precious metal layer formed on said nickel layer by an electroless precious metal plating,    a copper layer thinner than said nickel layer, formed on said first precious metal layer by an electroless copper plating, and    a second precious metal layer formed on said copper layer by an electroless precious metal plating.    
   
   
       8 . A circuit board as defined by  claim 7 , wherein said metal layer forming the pad body is formed of copper, and said first or second precious metal layer is formed of gold, palladium or platinum.